Locking arrangement for manually set printing wheels

ABSTRACT

A set of printing wheels with circumferentially spaced types and arresting recesses, can be set to digital printing positions by manual setting means. An axial row of spring biassed arresting pawls engages a row of the arresting recesses, and yield resiliently while the printing wheels are turned during setting to a selected number. The pawls have locking recesses cooperating with a locking bar extending at right angles to the direction of movement of the pawls to the arresting position. A carriage with a platen roller is manually moved out of an end position along a path over the printing wheels. The carriage is operatively connected with the locking bar so that the locking bar is ineffective in the end position of the carriage while the printing wheels are set, and engages the locking recesses in the pawls when the carriage moves out of the end position so that the wheels cannot be displaced by the platen roller during printing.

United States Patent 1 Tamiya 51 Dec. 4, 1973 LOCKING ARRANGEMENT FORMANUALLY SET PRINTING WHEELS [75] Inventor:

[73] Assignee: Janome Sewing Machine Co., Ltd.,

Tokyo, Japan 22 Filed: Oct. 6, 1972 21 Appl. No.: 295,496

Yoshimichi Tamiya, Tokyo, Japan [30] Foreign Application Priority DataOct. 9, 1971 Japan"... 46/9315?! [52] U.S. Cl. 101/45, 101/56 [51] Int.Cl B4lj l/28 [58] Field of Search 101/45, 56, 95, 99, 101/269 [56]References Cited UNITED STATES PATENTS 3,138,091 6/1964 Maul 101/453,334,582 8/1967 101/45 3,322,062 5/1967 101/45 3,279,369 10/1966 101/56X 3,494,282 2/1970 101/45 3,405,634 10/1968 Maulet a1. 101/45 PrimaryExaminer-Robert E. lulfrey Assistant ExaminerE. M. CovenAttorney-Michael S. Striker [57] ABSTRACT A set of printing wheels withcircumferentially spaced types and arresting recesses, can be set todigital printing positions by manual setting means. An axial row ofspring biassed arresting pawls engages a row of the arresting recesses,and yield resiliently while the printingwheels are turned during settingto a selected number.

The pawls have locking recesses cooperating with a locking bar extendingat right angles to the direction of movement of the pawls tothe'arresting position. A carriage with a platen roller is manuallymoved out of an end position along a path over the printing wheels. Thecarriage is operatively connected with the locking bar so that thelocking bar is ineffective in the end position of the carriage while theprinting wheels are 'set, and engages the locking recesses in the pawlswhen the carriage moves out of the end position so that the wheelscannot be displaced by the platen roller during printing.

10 Claims, 4 Drawing Figures PATENIEU BEE 41975 SHEET 10F 4 PATENIEUBEB4 l9?5 SHEET 30F 4 PATENTEDUEB 41925 3776130 SHEET u 0F 4 LOCKINGARRANGEMENT FOR MANUALLY SET PRINTING WHEELS BACKGROUND OF THE INVENTIONIt is known to use spring biased pawls for yieldingly arresting printingwheels in angularly displaced printing positions while the printingwheels are being set so that the correct number indication can beselected for each printing wheel. However, when a platen roller ismanually moved over a paper sheet covering the effective types of theset of printing wheels, it may happen that the printing wheels aredisplaced out-of the correct position. It has been proposedto lock theprinting wheels during the operation of the carriage and printingroller,

but the arrangements according to the prior art are complicated.

SUMMARY OF THE INVENTION It is one object of the invention toprov-idealock ing arrangement for manually set printi'ngwheel's which preventsany displacement of the set printingwheeis by a platen rollerpassingover the. printing wheels during the printing operation.

Another object of the invention is to improve airrangements according tothe prior art serving asirnilar purpose.

Another object ofthe inventionds to*lck arresting:

pawls against radial movementby. an axially extending locking bar. 1

Another object of the invention .is to make the operation ofthe. lockingbar dependingontheposition .of=the.:

manually operated carriage and'platenroller;

With'this objects in view, thepresent invention :provides a lockingarrangement for locking arresting pawls and thereby printingwheels bymeans of a lockingbar which is ineffectivezin one end positionoftthecarriage,

and effective when thecarria'ge moves with the. platen- BRIEFDESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view ofaprintingrnachineto which the present invention is applied;

FIG. 2.is a fragmentary perspective vlew illustrating,-

an embodiment of the invention;

FIG. 3 is a fragmentary side view, partially in section, illustratingthe embodiment of FIG. 2; and:

FIG. 4 is a fragmentary bottom view of the embodiment of FIGS. 2and3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,as best seenin FIG. 1, a manual printer has a casing lrand supports-acar riage .2'having a rotary platen roller-'3 for movement along a pathover the printing bed 4 which has a cutout 40, see 'alsorFIG.'-.3,'-through which a' segment shapedportion "of a set 55 of printingwheelsSprojects so that the'top. rowof types 5b is engaged bythe platenroller- 2 3. Each printing wheel 5 is integral with a gearfi h'avin'g'arresting recesses 6a which respectively correspond to types 5b, and toangular printing positions of the printing wheels 5. All printing wheelsand gears 5,.6 are mounted for free rotation; on a shaft 40 which issupported on the supporting frame means of the printer.

As shown in FIG. 1, a cover plate 7 is provided which has longitudinalslots 8 in which setting levers-.9 are guided so that rack bar portions1 1 of the setting levers 9 mesh with the gear portions 6 of thetypewheels 5, respectively. The setting levers 9 have head portions 10 onwhich buttons 10a are mounted after the assembly of the casing portion7. The rack portions 1 l are guided in a comb-shaped guide 12.

A set of arresting pawls 13 is arranged in a row and guided by guidemembers 20 for movement in radial direction into and out of thearresting recesses of the gear portions 6. A guide rod 18 having endsmounted in'the frame of the machine, passes through a slot 14 in eacharresting pawl 13 so that the arresting pawls can perform a slightangular movement for better fitting into the arresting recesses 6a intowhich they are biased by individual springs 19 located in blind bores 16at the rear ends of the arresting pawls 13 whose front ends 15 aretapered to conform to the shape of the arresting recesses 6a; a

The individual springs 19 urge the pawls 13 to the arresting positionillustrated in FIG. 3, but when the rack bars 11 of the setting means 9are longitudinally displaced by operation of the buttons 10, eachtoothof each gear 6 acts on the tapered end 15 of the respective pawl 13 tourge the respective pawl 13 out of the arresting recess 6a so that thepawls 13 yield against the actionof the small springs 19, and permit thesetting of the printing wheels 5 to diflerent angular printing positionsin'which difi'erent types 5b are located in an operative row on top ofthe type wheels 5. I

. Each arresting pawl 13 has a triangular locking recess 17, and whenthe arresting pawls 13 are in the arresting position fully engaging thearresting recesses 6a, all locking recesses 17 are aligned in an axialrow. A'bail 21 is mounted on a shaft 22 for angular movement, and hastwo arms 21;: between whicha locking bar 23 extends directly below the"row of locking recesses 17. A torsion spring 21b biasses bail 21 withlooking bar 23 to an inoperative position in which locking bar 23 is notlocated in-the row of locking recesses 17. An angular lever 24 ismounted on pivots 26 on the supporting frame 41 and has'one end 24aabutting the yoke portion of bail 21 and another end portion with apin27 located in a fork-shaped portion 30 at one end of another angularlever 28 which is mounted for angular movement on a stationary shaft 29secured to the machine frame. Angular lever 28 is biased by a spring 32in the direction of the arrow A so that the motion transmitting means28, 24, 21 are biassed by the locking spring 32 to move to a position inwhich the locking bar 23 is in the locking position illustrated in chainlines in FIG. 3 in which locking bar 23 engages the slanted edges of thelockingrecesses 17 of pawls 13.

One end of lever 28 is connected by a wire link 33 with a feeler lever34 which is mounted on a supporting shaft 34a for angular movement. Thecarriage 2 has on either side of the printing bed plate 4, a pair ofrollers 35 engaging the top and bottom faces of the bed plate 4 so thatthe carriage 2 with the platen roller 3 can move along a path from theend position shown in FIG.

l to another end position, and back. During such movement, the platenroller 3 moves over the top portion of the set 55 of printing wheelswhich projects out of output 4a in bed plate 4 so that an imprint can bemade on a sheet placed between platen roller 3 and the printing wheels5.

In the initial end position of carriage 2, a roller 35 is located in theregion of the feeler end 34b, as best seen in FIG. 4, so that spring 32cannot move feeler lever 34 to the position shown in broken lines.However, when the carriage 2 is manually moved out of the end positionof rest shown in FIG. 1 and FIG. 4, the respective roller 35' moves tothe position 35" shown in FIG. 4 in broken lines, and consequentlypermits feeler lever 34 to move to the broken line position due to theactionof spring 32. Since feeler lever 34 and wire link 33 are part ofthe motion transmitting means which also include members 28, 24, and 21,spring 32 acts through the motion transmitting means on locking bar 23so that locking bar 23 moves into the aligned row of locking recesses17, completely looking all pawls 13 against movement out of therespective arresting recesses 6a.

The locking is particularly effective since the pawls are mounted onguide rails 20 and on guide shafts 18 for substantially radial movementin relation to the axis of the printing wheels 5, while the locking bar23 extends in axial direction at right angles to the direction ofmovement of the arresting pawls 13. If one of the printing wheels 5 andgears 6 was not accurately set to a printing position so that thetapered end of the respective pawl 13 is not fully located in thearresting recess 6a, the corresponding locking recess is also slightlydisplaced, but the locking bar 23 engaging the slanted walls of therespective locking recess 17, forces the pawl 13 to assume the correctarresting position, and the slanted edges of the front portion 15 of therespective arresting pawl 13 urge respective gear 6 and printing wheel 5to the correct printing position.

During operation of the apparatus, a sheet is placed on the printing bedabove the set 55 ofprinting wheels 5 and held by paper guides 1a shownin FIGS. 1 and 3. The sheet, not shown, is located between theprojecting portion of the set 55 of printing wheels 5 and the plane inwhich the platen roller 3 moves during movement of the carriage 2. Whenthe carriage is in the end position of rest on the left of the printingbed 4, as shown in FIG. 1 and FIG. 4, in solid lines, feeler lever 34 isheld in the solid line position shown in FIG. 4 so that the motiontransmitting means 28, 24, 21 hold the locking bar 23 in the solid lineposition of FIG. 3 outside of the row of locking recesses 17, as shownin FIG. 3. Consequently, arresting pawls 13 are biassed only by springs19 into the arresting position engaging the arresting recesses 6a. Whenthe printing wheels 5 are now set by movement of the setting means 9with rack bars 11, the gears 6 turn together with the respective typewheels 5, and all type wheels are successively set to a selectedprinting position for printing the number represented by the uppermosttypes 5b on the type wheels 5 which are located under the paper sheet.

In order to produce an imprint, it is necessary to move the carriage 2with platen roller 3 out of the position of rest and over the printingrollers 5. Such a movement may cause displacement of individual printingwheels 5 and corresponding displacement of the arresting pawls l3 sothat the numbers would not be accurately printed. When carriage 2 movesout of the end position of rest, the carriage roller 35 moves out of thesolid line position to the position 35 shownin broken lines. Feelerlever 34 is released, and permits angular movement of motiontransmitting lever 28 about the axis of the stationary shaft 29 due tothe action of the locking'spring 32. Pin 27 of motion transmittingmember- 24 is displaced by the fork-shaped portion 28a about the axis ofshaft 26 so that end portion 24a urges bail 21 out of the solid lineposition shown in FIG. 3 to the broken line position so that the lockingbar 23 is moved from the inoperative position shown in solid lines tothe operative position shown in broken lines, and all pawls 13 arelocked against any movement out of the corresponding arresting recesses6a. Consequently, a displacement of the printing wheels out of aselected angular printing position is impossible, and a selected numberis accurately printed along a straight line.

Due to the fact that during the setting operation only the small springs19 yield when a tooth of gear 6 passes the front end 15 of therespective pawl 13, the wear on the teeth 6 and recesses 6a is small.Due to the fact that the locking bar extends at right angles to thedirection of movement of the pawls 13, the pawls 13 are mechanicallylocked by the locking bar 23 against any yielding movement out of thearresting recesses 64, and it is not by spring force that the arrestingpawls 13 are locked against movement out of the arresting recesses 6a.

However, if an arresting recess 17 is misaligned, the force of thestrong spring 32 is available for urging the locking bar 23 into themisaligned locking recess 17 so that the respective pawl 13 and printingwheel 5 are adjusted to the correct positions in which the respectiveselected and set type of the printing wheel 5 is placed in the correctposition for printing. When the locking bar 23 fully engages all lockingrecemes 17, all printing wheels are in correct printing position, and itis impossible for the platen roller 3 to displace the printing wheelsand printing types, particularly due to the fact that the locking bar 23extends transverse to the direction of movement of the pawls, and thatno yielding of the locking bar 23 is possible in the locking position oflocking bar 23. i

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types oflocking arrange- Without further analysis, the foregoing will SOfullyreveal the gist of the present invention that others can byapplying current knowledge readily adapt it for various applicationswithout omitting features that, from the standpoint of prior art, fairlyconstitute essential characteristics of the generic or specific aspectsof this invention and, therefore, such adaptations should and areintended to be comprehended within the meaning and range of equivalenceof the following claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

I claim:

1. Locking arrangement for manually set printing wheels, comprisingsupporting means; carriage means including a platen roller and beingsupported on said. supporting means for movement with said platen rolleralong a path between two end positions; a set of printing wheel meansmounted on said supporting means for independent angular movement aboutan axis between a plurality of angular printing positions, and having aplurality of types and a plurality of arresting recesses associated withsaid angular printing positions, respectively; a set of setting meansfor turning said printing wheel means to selected angular printingpositions, respectively, so that an axial row of selected types islocated in said path of said platen roller; a set of arresting pawlsarranged in an axial row opposite an axial row of arresting recesses,said pawls being movable in a substantially radial direction to and fromarresting positions located in said arresting recesses, respectively,and having locking recesses forming an axial row when said pawls arelocated in said arresting recesses in said arresting positions;arresting spring means for biassing said pawls to said arrestingpositions so that said pawls resiliently yield when said type wheelmeans are angularly displaced by said setting means; locking meansincluding a locking bar movable between an inoperative position spacedfrom said pawls, and a locking position located in said row of lockingrecesses, said locking bar in said locking position extending in axialdirection at right angles to said radial direction so that said pawlsare locked in said arresting recesses; and motion transmitting meansconnecting said carriage means with said locking means and holding saidlocking bar in said inoperative position when said carriage means is inone of said end positions so that said type wheel means can be set bysaid setting means, and holding said locking bar in said lockingposition when said carriage means moves out of said one end position sothat said printing wheel means can not be angularly displaced out ofselected angular printing positions by said platen roller moving alongsaid path.

2. Locking arrangement as claimed in claim 1 wherein said lockingrecesses have slanted edges so that when said locking bar enters amisaligned locking recess of a pawl which is not fully in said arrestingposition due to a wrong angular position of the respective printingwheel means, said locking recess is aligned by said locking bar with thelocking recesses of the other pawls whereby the respective pawl isplaced in said arresting position for holding said printing wheel meansin the respective angular printing position.

3. Locking arrangement as claimed in claim 1 wherein said motiontransmitting means include locking spring means for urging said motiontransmitting means to hold said locking bar in said locking position,and feeler means biassed by said locking spring means to engage aportion of said carriage means only when said carriage means is in saidone end position for bolding said locking bar in said inoperativeposition whereby when said carriage means moves out of said one endposition and along said path, said portion releases said feeler means sothat said locking spring means causes movement of said locking bar tosaid locking position.

4. Locking arrangement as claimed in claim 3 wherein said locking bar ismoved by said motion transmitting means to said locking position in adirection transverse to said radial direction.

5. Locking arrangement as claimed in claim 3 wherein said carriage meansincludes a carriage on which said platen roller is mounted for rotation,and wherein said portion of said carriage meansis a roller rotatablymounted on said carriage and rolling along said path on said supportingmeans.

6. Locking arrangement as claimed in 'claim 5 wherein said supportingmeans include a printing bed formed with a cutout through which said setof printing wheels partly projects,said cutout being located in saidpath.

7. Locking arrangement as claimed in claim 3 wherein said motiontransmitting means include a bail mounted for angular movement about abail axis on said supporting means and having two arms located at theends of said row of pawls, said locking bar being mounted on the ends ofsaid arms; and wherein said feeler means includes a feeler lever mountedon said supporting means for angular movement and being biassed by saidlocking spring means to engage said car.- riage portion in said one endposition of said carriage means.

8. Locking arrangement as claimed in claim 7 wherein said set of pawlsis located in a plane passing through said axis; and wherein said bailaxis is parallel to said axis so that said locking bar movessubstantially perpendicularly to said plane from said inoperativeposition to said locking position.

9. Locking arrangement as claimed in claim '1 wherein each printingwheel means includes a printing wheel having circumferentially spacedtypes, and a gear po'rtionhaving teeth and said arresting recessesbetween said teeth.

10. Locking arrangement as claimed in claim 8 wherein said set ofsetting meansincludes a set of rack bars meshing with. said gearportions of said printing wheels, respectively.

1. Locking arrangement for manually set printing wheels, comprisingsupporting means; carriage means including a platen roller and beingsupported on said supporting means for movement with said platen rolleralong a path between two end positions; a set of printing wheel meansmounted on said supporting means for independent angular movement aboutan axis between a plurality of angular printing positions, and having aplurality of types and a plurality of arresting recesses associated withsaid angular printing positions, respectively; a set of setting meansfor turning said printing wheel means to selected angular printingpositions, respectively, so that an axial row of selected types islocated in said path of said platen roller; a set of arresting pawlsarranged in an axial row opposite an axial row of arresting recesses,said pawls being movable in a substantially radial direction to and fromarresting positions located in said arresting recesses, respectively,and having locking recesses forming an axial row when said pawls arelocated in said arresting recesses in said arresting positions;arresting spring means for biassing said pawls to said arrestingpositions so that said pawls resiliently yield when said type wheelmeans are angularly displaced by said setting means; locking meansincluding a locking bar movable between an inoperative position spacedfrom said pawls, and a locking position located in said row of lockingrecesses, said locking bar in said locking position extending in axialdirection at right angles to said radial direction so that said pawlsare locked in said arresting recesses; and motion transmitting meansconnecting said carriage means with said locking means and holding saidlocking bar in said inoperative position when said carriage means is inone of said end positions so that said type wheel means can be set bysaid setting means, and holding said locking bar in said lockingposition when said carriage means moves out of said one end position sothat said printing wheel means can not be angularly displaced out ofselected angular printing positions by said platen roller moving alongsaid path.
 2. Locking arrangement as claimed in claim 1 wherein saidlocking recesses have slanted edges so that when said locking bar entersa misaligned locking recess of a pawl which is not fully in saidarresting position due to a wrong angular position of the respectiveprinting wheel means, said locking recess is aligned by said locking barwith the locking recesses of the other pawls whereby the respective pawlis placed in said arresting position for holding said printing wheelmeans in the respective angular printing position.
 3. Lockingarrangement as claimed in claim 1 wherein said motion transmitting meansinclude locking spring means for urging said motion transmitting meansto hold said locking bar in said locking position, and feeler meansbiassed by said locking spring means to engage a portion of saidcarriage means only when said carriage means is in said one end positionfor holding said locking bar in said inoperative position whereby whensaid carriage means moves out of said one end position and along saidpath, said portion releases said feeler means so that said lockingspring means causes movement of said locking bar to said lockingposition.
 4. Locking arrangement as claimed in claim 3 wherein saidlocking bar is moved by said motion transmitting means to said lockingposition in a direction transverse to said radial direction.
 5. Lockingarrangement as claimed in claim 3 wherein said carriage means includes acarriage on which said platen roller is mounted for rotation, andwherein said portion of said carriage means is a roller rotatablymounted on said carriage and rolling along said path on said supportingmeans.
 6. Locking arrangement as claimed in claim 5 wherein saidsupporting means include a printing bed formed with a cutout throughwhich said set of printing wheels partly projects,said cutout beinglocated in said path.
 7. Locking arrangement as claimed in claim 3wherein said motion transmitting means include a bail mounted forangular movement about a bail axis on said supporting means and havingtwo arms located at the ends of said row of pawls, said locking barbeing mounted on the ends of said arms; and wherein said feeler meansincludes a feeler lever mounted on said supporting means for angularmovement and being biassed by said locking spring means to engage saidcarriage portion in said one end position of said carriAge means. 8.Locking arrangement as claimed in claim 7 wherein said set of pawls islocated in a plane passing through said axis; and wherein said bail axisis parallel to said axis so that said locking bar moves substantiallyperpendicularly to said plane from said inoperative position to saidlocking position.
 9. Locking arrangement as claimed in claim 1 whereineach printing wheel means includes a printing wheel havingcircumferentially spaced types, and a gear portion having teeth and saidarresting recesses between said teeth.
 10. Locking arrangement asclaimed in claim 8 wherein said set of setting means includes a set ofrack bars meshing with said gear portions of said printing wheels,respectively.